在天愿作比翼鸟,
在地愿为连理枝.
这一句许渊冲的版本是：
On high,we'd be two love birds flying wing to wing,
On earth,two trees with branches twined from spring to spring.
另外两个版本分别是：
（That） we wished to fly in heaven,two birds with the wings of one,
And to grow together on the earth,two branches of one tree.
To fly together in the sky,two birds on the same wing,
To grow together on the earth,two branches of one tree.
个人觉得最后一个版本似乎比较舒服,不知您觉得如何?